> So, leave COUNT(*) alone. But it would be very handy to have a > way to get an approximate table size that is more accurate than is > provided by a pg_class.reltuples that is only updated on vacuums.
Create 2 sequences, one for counting tuple additions and one for counting tuple deletions. When you INSERT a tuple, bump the "added" sequence (select nextval()); When you DELETE a tuple, bump the "deleted" sequence (select nextval()); To retrieve an approximate count, take the current value of both sequences (select directly -- don't use currval) and subtract the "deletes" from the "adds". This is a very fast tracking mechanism with the catch that it does not handle rollbacks -- but you only wanted approximate. Put all of the logic inside a pair of triggers and a function within the DB. -- ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
